1. Field of the Invention
The present invention relates to a magnetic sensor and, in particular, relates to a magnetic sensor that includes a magnetoresistive element.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 11-274598, Japanese Unexamined Patent Application Publication No. 9-102638, International Publication No. 2013/171977, Japanese Unexamined Patent Application Publication No. 2012-88225 and Japanese Unexamined Patent Application Publication No. 2013-250182 disclose magnetic sensors that improve the isotropy of magnetic field detection.
The pattern of a magnetoresistive element of the magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 11-274598 has a spiral shape. The two ends of the spiral-shaped pattern are formed at the outermost parts of the pattern located on opposite sides to each other. The pattern of the magnetoresistive element is substantially formed of curved portions.
In the magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 9-102638, a magnetoresistive element has a circular shape formed by being wound through a plurality of turns in a spiral shape, and is formed through film deposition so as to be isotropic with respect to an external magnetic field.
In the magnetic sensor disclosed in International Publication No. 2013/171977, each of a plurality of magnetoresistive elements of a bridge circuit is connected so as to be successively folded back, with plural portions that extend in a direction that is substantially orthogonal to the overall magnetic field direction being arrayed in parallel at specific intervals, and each of the plural portions is connected to be successively folded back, formed in a zigzag state that is electrically connected, with multiple portions that extend in the magnetic field detection direction being arrayed parallel at specific intervals.
The magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 2012-88225 is formed by connecting two magnetoresistive elements, which each have a shape formed by continuously connecting semicircular arc-shaped patterns of different diameters, in parallel with each other.
In the magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 2013-250182, the center of a first sensing part having a regular octagon shape and the center of a second sensing part having a regular octagon shape are aligned with each other and the first sensing part is arranged outside the second sensing part. The linear layout of a second magnetoresistive element of the second sensing part is inclined at 22.5° with respect to the linear layout of a first magnetoresistive element of the first sensing part.
The magnetic sensors disclosed in the first four publications discussed above include a substrate that has a rectangular shape in plan view. Consequently, when the outer shape of a magnetoresistive element is a shape other than a rectangular shape in plan view, there is likely to be excess space around the magnetoresistive element. Therefore, it would be possible to further reduce the size of the magnetic sensors.
Thus, it is desirable to further improve the isotropy of magnetic field detection in the magnetic sensors disclosed in the publications discussed above.